U.S. patent number 4,021,604 [Application Number 05/567,792] was granted by the patent office on 1977-05-03 for flexible conduit connector.
This patent grant is currently assigned to AMP Incorporated. Invention is credited to Frank Peter Dola, Frederick William Rossler, Jr..
United States Patent |
4,021,604 |
Dola , et al. |
May 3, 1977 |
Flexible conduit connector
Abstract
A connector for affixing a flexible conduit having external
helical grooves to an electrical junction box is disclosed. The
connector comprises a stamped and formed metallic retaining clip in
conjunction with a rigid housing. The clip engages the helical
grooves and also establishes contact with a circular hole in one
face of the junction box. Both a secure mechanical and electrical
connection are established so that the metallic conduit and the
metallic junction box can serve as a continuous electrical ground.
A straight-through and a right angle version of the connector are
disclosed. The retaining clip is mounted in the housing so that the
connector snaps into the circular hole and can be removed without
damage.
Inventors: |
Dola; Frank Peter (Port Richey,
FL), Rossler, Jr.; Frederick William (New Port Richey,
FL) |
Assignee: |
AMP Incorporated (Harrisburg,
PA)
|
Family
ID: |
24268665 |
Appl.
No.: |
05/567,792 |
Filed: |
April 14, 1975 |
Current U.S.
Class: |
174/51; 174/659;
285/154.2 |
Current CPC
Class: |
H02G
3/0616 (20130101) |
Current International
Class: |
H02G
3/06 (20060101); H02G 3/02 (20060101); H02G
003/06 (); H02G 003/08 () |
Field of
Search: |
;174/65R,51
;285/162,158,189,319 ;403/201,299,329 ;339/14R,126R,128 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Truhe; J. V.
Assistant Examiner: Tone; David A.
Attorney, Agent or Firm: Pitts; Robert W. Raring; Frederick
W. Keating; William J.
Claims
What is claimed is:
1. A connector member for establishing an electrical and mechanical
connection between a flexible electrical conduit having helical
grooves and a metallic junction box having a circular opening for
receipt of said flexible conduit, said connector member
comprising:
metallic clip means, said clip means having a central web portion
and two sidewall portions, said web portion having an opening
therein for receipt of said flexible conduit, each of said sidewall
portions having latching means thereon for resiliently establishing
contact with the edges of said circular opening on said junction
box, and
rigid housing means, said housing means having a passage extending
therethrough for partial receipt of said flexible conduit and for
receipt of the wires contained in said conduit, said housing means
having two slots for receipt of said sidewall portions and a
tubular extension which may be inserted into said circular opening,
the axis of said tubular extension being aligned with said slots so
that said latch means may be positioned on opposite sides of said
tubular extension, whereby
said flexible conduit may be inserted into said opening and secured
to said clip means and said tubular extension may in turn be
inserted into said opening on said junction box and by the action
of said latch means a secure mechanical connection is established
and the electrical connection formed allows said junction box and
said conduit to serve as a continuous ground.
2. A connector member for establishing an electrical and mechanical
connection between a flexible electrical conduit having exterior
helical grooves and a panel member, such as a face of a metallic
electrical junction box, having a circular opening of a
predetermined diameter, said connector member comprising:
a rigid housing for supporting a metallic retaining clip, said
rigid housing having a generally tubular section with a diameter
substantially equal to, and less than, said predetermined diameter,
said tubular section having a specified number of external flat
sides, said housing also having an enlarged section for receiving
the end of said conduit, said enlarged section having a specified
number of slots for receiving said retaining clip, said rigid
housing having an internal passage opening onto one surface of said
enlarged section and extending through said enlarged section to and
through said tubular section,
a stamped and formed metallic retaining clip, said retaining clip
having a central web portion and a specified number of sidewall
portions extending from the periphery of said web portion, said web
portion and said sidewall portions being generally flat with said
sidewall portions being bent over with respect to said web portion,
said sidewall portions being essentially parallel to the axis of
said tubular section and perpendicular to said web portion,
conduit gripping means on said retaining clip, said gripping means
comprising oppositely deflected segments of said retaining clip
bent to engage said exterior helical grooves, and
latching means on said sidewall portions, said sidewall portions
extending through said slots with said latching means thereby being
located beside and spaced from said flat sides of said tubular
section, said latching means having exposed edges for contacting
the inner circumference of said circular opening, whereby
said conduit may be mechanically and electrically attached to said
junction box so that a continuous ground is established between
said conduit and said junction box.
3. A connector member as set forth in claim 2 wherein said metallic
retaining clip consists of one integral metal strip.
4. A connector member as set forth in claim 2 wherein said metallic
retaining clip has two sidewalls portions extending from opposite
sides of said web said sidewalls being parallel to each other and
said housing has two slots and two flat sides on said tubular
section on opposite sides thereof.
5. A connector member as set forth in claim 2 wherein said internal
passage has an internal stop which prevents said flexible conduit
from extending completely through said internal passage.
6. A connector member as set forth in claim 2 wherein said conduit
gripping means is located in said web portion, said conduit
gripping means comprising a hole in said web portion which is
aligned with said internal passage with said deflected segments
being disposed around said hole in said web portion.
7. A connector member for establishing an electrical and mechanical
connection between a flexible electrical conduit having helical
grooves and a panel member such as a face of a metallic electrical
junction box, having a circular opening of a pre-determined
diameter, said conduit extending substantially parallel to said
face, said connector member comprising:
a rigid housing having a generally rectilinear section, said
rectilinear section having first and second faces, said second face
being substantially perpendicular to said first face, said first
face having a specified number of slots extending therethrough and
said second face having a hole extending therethrough, said hole
having a diameter which is substantially equal to, but greater
than, the diameter of said conduit,
a generally tubular section extending from said first face to said
housing, said tubular section having a diameter substantially equal
to, but less than, said pre-determined diameter and also having a
specified number of external flat surfaces, said external flat
surfaces being in alignment with said slots on said first face,
a generally right-angular continuous internal passage extending
from said hole in said second face to and through said tubular
section,
a stamped and formed metallic retaining clip having a central web
portion and a specified number of sidewall portions extending from
the periphery of said web portion, said web portion and said
sidewall portions being generally flat with said sidewall portions
being bent over with respect to said web portion, said sidewall
portions being generally parallel to the axis of said tubular
section and generally perpendicular to said web portion, said web
portion being positioned on the inside of said housing with said
sidewall portions extending through said slots in said first
face,
conduit gripping means on said retaining clip, said gripping means
being positioned on the inside of said housing and adjacent to said
second face, and
latching means on the ends of said sidewall portions, said latching
means being located on the outside of said housing and being beside
and spaced from said flat sides of said tubular section, said
latching means having exposed edges for contacting the inner
circumference of said circular opening, whereby,
said conduit may be inserted into said hole in said second face and
said gripping means can then secure said conduit while the wires in
said conduit pass through said internal passage and into said
junction box which has been mechanically and electrically attached
to said conduit by the latching means on said connector.
8. A connector member as set forth in claim 7, wherein said
rectilinear section has a third face parallel to said first face
and adjoining said second face, portions of said third face
comprising a hinged cover member, said cover member being attached
to said rectilinear section and being movable with respect thereto
so as to facilitate passage of said wires through said housing, a
part of said cover member bearing against said inner circumference
of said circular opening when said connector member is attached to
said junction box.
9. A connector member as set forth in claim 7, wherein said
gripping means comprise deflected segments of said retaining clip,
some of said deflected segments extending from said web portion and
the remainder of said deflected segments extending from two of said
sidewall portions.
10. In combination with a flexible metallic conduit and an
electrical junction box having a circular opening in one face
thereof, a connector assembly comprising:
a rigid housing of electrically insulating material, said housing
having a generally tubular portion extending through said circular
opening and an enlarged portion located flush against the outer
surface of said one face,
an open-ended internal passage extending through said tubular
portion and said enlarged portion, with said conduit extending
partially into said internal passage,
a metallic clip mounted on said housing and having a central web
and a plurality of sidewalls extending transversely from the
periphery of said web,
a hole in said central web in alignment with said internal passage,
the edges of said hole forming a mechanical and electrically
grounding connection with said metallic conduit, and
gripping edges on said sidewalls forming a mechanical and
electrically grounding connection with the edges of said one face,
said gripping edges and said enlarged portion acting in conjunction
to secure said connector assembly to said one face of said junction
box.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improved snap-in connector for
attaching a helically grooved flexible conduit to a panel like
member such as an electrical junction box containing a circular
hole in one face.
2. Description of the Prior Art
One standard method for connecting a flexible electrical conduit
having external helical grooves to a junction box has been to
employ a die cast threaded sleeve and nut assembly. Another method
has been to employ a snap-in flexible clip assembly. These snap-in
assemblies are metallic and are generally tubular in shape. One
specific snap-in connector is disclosed in U.S. Pat. No.
3,858,151.
SUMMARY OF THE INVENTION
This invention relates to a connector for attaching helically
grooved electrical conduit to a junction box. The connector
disclosed herein comprises a substantially flat stamped and formed
metallic clip and a rigid housing. This connector can be inserted
into a hole in the junction box with the metallic clip providing a
resilient latching means. The metallic clip can also be threadably
attached to the helically grooved conduit. The rigid housing
provides support for the metallic clip as well as completely
filling the hole. Similar connector housings for attaching conduits
which are either parallel or perpendicular to the junction box are
disclosed and claimed.
Among the objects of this invention are the provision of an
inexpensive connector employing a stamped and formed metallic clip
and an easily molded rigid housing. Additionally, this connector is
envisioned as providing a suitable continuous electrical ground as
well as a secure mechanical connection. Another object is to
provide both a right angle and straight-in version of this
connector, both employing an inexpensive clip and housing. A hinged
cover is utilized with the right angle version to facilitate easy
insertion of the wires contained in the conduit. A further object
of this invention is to provide a snap-connector which may be
removed without destroying the connector. Finally, this connector
is contemplated as providing a reproducible contact with the
junction box which is not dependent upon the installer.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows a helically grooved circuit with a straight-in
connector and a right angle connector attached to opposite
ends.
FIG. 2 shows a flat stamped blank prior to being formed into a
retaining clip.
FIG. 3 shows a telescopic view of the straight-in connector showing
the retaining clip with the legs bent downward just above the
straight-in housing.
FIG. 4 shows a cut-away view of the straight-in connector inserted
into a junction box.
FIG. 5 shows details of the latching means employed with this
connector.
FIG. 6 shows a blank of the right angle retaining clip prior to
being formed into its final configuration.
FIG. 7 shows the right angle housing with its hinged cover
member.
FIG. 8 shows the right angle retaining clip in its final
configuration.
FIG. 9 shows the right angle connector with the retainer clip
inserted into the right angle housing.
DETAILED DESCRIPTION OF THE DRAWING
FIG. 2 shows a stamped blank suitable for forming the straight-in
retaining clip. This blank has two legs or sidewalls 8 and 8' on
opposite sides of a central web 6. The dashed lines represent fold
lines about which the sidewalls will be bent with respect to the
central web. Since the two sidewalls are basically the same,
corresponding structures on the second sidewall are identified by
primed numerals. This practice will be used for the embodiment of
FIG. 2 and the embodiment of FIGS. 6 and 8. The central web 6 has a
central opening 23 with segments 26 and 28 extending partially
therearound. Opposed sidewalls 8 have notches 10, 10' located at a
point spaced from the central web. These notches define flap-like
members 17 and 17' on the end of each sidewall.
FIG. 3 is a telescoped view showing both the retaining clip 4 and
the straight-in housing 34. The two side-walls 8 and 8' of
retaining clip 4 have been bent over with respect to the central
web 6 and in this embodiment sides 8 and 8' are essentially
parallel to each other and perpendicular to central web portion 6.
Each sidewall contains two tabs 18 and 20 which have been struck
from the sides thereof. Tab 20 is located between notches 10 and
web 6. Tab 18 is located between notches 10 and the end of the
sidewall. Each of these tabs is deflected outwardly. The inner
portion 16 of the sidewalls proximate to the ends of each sidewall
have been curved. The segments 26 and 28 surrounding central
opening 23 have been deflected in opposite directions. Segment 26
has been raised with respect to the plane of web 6 and segment 28
has been depressed with respect to web 6. Such opposed deflection
causes the innermost edge of central opening 23 formed by the edges
of segments 26 and 28 to define a partial helix. This helix is
formed because segments 26 and 28 are of varying widths with
reference to the circular hole in web 6 defined by the forming
operation.
FIG. 3 also shows the straight-in rigid housing 34. This housing
has a central passage 40 extending from upper surface 42 to lower
surface 44. An enlarged section 36 constitutes the upper half of
the housing while a smaller tubular section 38 comprises the lower
half. This tubular section has opposed flat surfaces 39, 39'. The
enlarged section has slots 46, 46' extending therethrough. These
slots are parallel to flat surfaces 39, 39' and to the central
passage 40. Tubular section 38 has an outer diameter which is
slightly less than that of the opening in the junction box and can
be inserted into that opening. Enlarged section 36 will then fit
over the junction box opening completely covering it.
FIGS. 1, 4 and 5 show the straight-in connector as used in
attaching a helical conduit to one wall of a junction box 54. Each
of these figures is a cut-away exposing the action of certain
elements of the connector. It can be seen that deflected segments
26 and 28 threadably engage the exterior helical grooves so that
the conduit is firmly affixed to the connector. In FIG. 4, the
conduit extends into the central internal passage 40 and abuts an
interior stop 41 located within tubular section 38. The conductors
3 extend completely through internal passage 40 and the smooth
surface of the housing 34 in the neighborhood of stop 41 provides a
measure of protection for the insulation on the conductors. These
conductors will bear against this smooth surface of the housing and
the insulation on the conductors will not be damaged. FIGS. 4 and 5
demonstrate the manner in which the latching means on the retaining
clip 4 dig into the wall of junction box 54. The edges of the
junction box fit into notches 10 and 10' in the neighborhood of the
inner circumference of the circular opening in the junction box. A
sufficient electrical connection is established because of the
resultant digging action. Tab 18 also digs into the wall of
junction box 54 and also prevents the direct removal of the
connector from the junction box. Upon examining FIG. 3, it can be
seen that latching flaps 17 will be spaced from flat surfaces 39,
39' in the assembled connector. This spacing allows the connector
to be removed from the junction box without damaging the connector.
Removal is accomplished by inwardly deflecting sidewall portions 8
and 8' until they are in contact with flat surfaces 39 and 39'.
When deflected in this manner, tab 18 and notches 10 and 10' no
longer engage the wall of the junction box and the connector can be
pulled from the hole in the junction box.
In addition to providing a secure mechanical connection between
conduit 1 and junction box 54, this connector must also establish
an electrical connection between the conduit and the junction box.
Such an electrical connection is necessary if the cable and
junction box are to serve as a continuous ground. A volt meter is
schematically shown in FIG. 4. This volt meter is attached to a
point on the conduit and a point on the junction box. This
embodiment of the connector is capable of providing an electrical
connection which will ensure that if a current of 30 amperes were
flowing through the volt meter shown, there would be a voltage drop
of not more than 50 milivolts. This is a standard specification for
connectors of this type. This specification can be met by using a
metallic clip of 24 gauge galvanized steel and a rigid housing of a
phenolic plastic. Such a connector can also resist sufficient
tensile forces on the conduit and withstand suitable vibration and
heat limits.
FIGS. 6 and 8 show a metallic retaining clip 58 for use in a right
angle version of this connector. FIG. 6 shows a stamped blank prior
to being formed into the final configuration shown in FIG. 8. The
blank shown in FIG. 6 is bent along the fold lines indicated in
FIG. 6 and a number of tabs are struck into the blank at the
locations shown. Metallic clip 58 consists of a central web portion
60 with sidewall portions 62, 62' on opposite ends thereof. As with
the straight-in version of this connector, the side-wall portions
are bent so that they are parallel to each other and perpendicular
to web 60. The sidewall portions 62, and 62' have latching legs 64,
64' constituting the ends thereof. These latching legs are
essentially the same as the latching means shown in the straight-in
version of FIG. 3. They operate in the same manner as discussed in
connection with FIGS. 4 and 5. Notches 68 and 68' correspond to
notches 10 and 10', flaps 66 and 66' correspond to flaps 17, 17'
and tabs 76 and 76' correspond to tabs 18 and 18'.
The means for gripping conduit 1 with the right angle version
differs from the central opening 23 of the straight-in clip 4. The
right-angle clip 58 has four arms which together serve as the
gripping means for the conduit. Two arms 82 extend from the central
web portion 60 while arms 86, 86' extend from opposite sidewall
portions. Each of these arms is bent as shown in FIG. 8. These arms
will then define a helix in much the same manner as the deflected
segments 26 and 28 for the straight-in version. The external
grooves on the conduit can then be screwed into the gripping means
formed by the four arms. A tab 90 is struck inwardly from central
wall 60 to form a conduit stop. Tabs 78, 78' and 80 are struck
outwardly from central web portion 60. These three tabs serve to
anchor retaining clip 58 in the right angle housing 92.
FIG. 7 shows details of the right angle housing 72. This housing
comprises a rectilinear enlarged section 98 and a tubular section
100. Slots 106, 106' are located in the bottom of rectilinear
section 98 and are parallel to the flat sides 102, 102' of tubular
section 100. Slots 106, 106' receive sidewall portions 62, 62' just
as slots 46, 46' receive the straight-in sidewalls. FIG. 9 shows a
tubular conduit mating extension 110, extending from the backwall
108 of rectilinear section 98.
An additional feature of the right angle housing is the hinged
cover member 94 which serves as the front face of housing 92. A
flexible strip 96 attaches cover member 94 to rectilinear section
98. Cover member 94 has a partial tubular section 104 which serves
to complete tubular section 100. This hinged cover member
facilitates the insertion of wires 3 into the holes in the junction
box. These wires can now be bent about a right angle and placed in
the internal passage 93 which extends from conduit mating extension
110 through rectilinear section 98 and then through tubular section
100. After wires 3 are bent in this manner, cover member 94 may be
rotated to its closed position which is shown in FIG. 9. The
connector is then ready for insertion into a hole in the junction
box. Note that when the connector is inserted into a junction box,
extension 94 will abut the edge of the junction box and any
vibration or tension applied will cause any force on member 94 to
be supported by the junction box rather than by a flexible strip
96. FIG. 9 also shows that tubular mating extension 110 is
dimensioned so that arms 82, 86 and 86' are partially supported by
backwall 108.
The two embodiments herein disclosed present the essence of this
invention. Other embodiments which would still incorporate the
essence of this invention can be readily visualized. For instance a
connector incorporating three or more sidewalls would differ from
the embodiments shown by only an insignificant detail.
* * * * *